> It doesn't make sense to call thread_group_cputime() under task_lock(),> we can drop this lock right after we read get_mm_rss() and save the> value in the local variable.> > Note: probably it makes more sense to use sum_exec_runtime instead> of utime + stime, it is much more precise. A task can eat a lot of> CPU time, but its Xtime can be zero.> > Signed-off-by: Oleg Nesterov <oleg@redhat.com>